in city driving is where i seem to run out of brakes,its a pretty small vacuum booster(ford style) pretty tight under there!
i'll take a look at the check valve,it might be something i've overlooked.
before i spend $300.00 on a pump maybe the smart thing to do would be
to slam in a vacuum can & see if that helps?
after all i could always sell it at a swap meet in the spring!